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Dec. 13, 2007 – Dual antiplatelet therapy is extremely important after implanting a drug-eluting stent to open a blocked coronary artery, according to updated joint Guidelines for Percutaneous Coronary Intervention from the American College of Cardiology, American Heart Association and Society for Cardiovascular Angiography and Interventions. The guidelines, an update of the 2005 recommendations, are in online issues of Circulation: Journal of the American Heart Association, Journal of the American College of Cardiology and Catheterization and Cardiovascular Interventions: Journal of the Society for Cardiovascular Angiography and Interventions.
The guidelines note that the artery-opening procedure called percutaneous coronary intervention (PCI) is effective in treating a heart attack and a very useful method to treat symptoms of angina. As expected, research has identified a few caveats.
In PCI, also known as angioplasty, a thin catheter is inserted in an artery in the inner thigh and threaded up to the heart to the blockage causing the heart attack or severe obstruction causing symptoms of angina. A small balloon is then inflated to push back the blockage and restore blood flow to the heart. A wire mesh tube called a stent is usually put in place to prop open the artery and prevent re-blocking.
In the past several years, drug-coated – also called drug-eluting – stents have been used. The drug on the stent helps even more to prevent the artery from becoming blocked again. However, these coated stents have a slightly higher risk of clots forming inside them, so patients who receive them must take a combination of anti-clotting medicines for a year or longer after their procedure.
Because of the higher risk of in-stent clotting, the guideline writing committee emphasizes the importance of dual antiplatelet therapy after drug-eluting stents (DES). This requirement increases the patient’s responsibility in treatment to ensure successful stenting.
The guideline writing group recommended that a DES should be considered as an alternative to a bare-metal stent in those patients for whom clinical trials indicate a favorable effectiveness and safety profile, but emphasized that it’s very important before performing the procedure to be sure that after receiving the DES the patient can comply with the dual antiplatelet therapy of aspirin and clopidogrel.
The guidelines state that at least one year of clopidogrel therapy is required and possibly a longer administration may be considered in patients undergoing DES placement. Thus, “before implanting a drug-eluting stent, the interventional cardiologist should discuss with the patient the need for and the duration of dual antiplatelet therapy (clopidogrel plus aspirin) and confirm the patient’s ability to comply with the recommended therapy.” Members of the writing group emphasized that it is important that patients be actively involved in the decision, because their participation is necessary for successful treatment.
Continuing dual antiplatelet therapy is so important that the guidelines take into consideration future medical procedures that may require the therapy to be interrupted. If patients face additional surgery, recommendations call for implanting a bare-metal stent or performing a balloon angioplasty with provisional stent implantation instead of the routine use of a DES.
In addition to recommendations on stents, the update addresses the timing of PCI in certain groups of patients and various clinical settings. The update reviews research published through late 2006 on the treatment strategy of “facilitated” PCI by performing fibrinolysis immediately before being transferred for PCI. Also, the update incorporates the results of research examining whether PCI is useful and efficient for re-opening completely blocked arteries in patients with one- or two- vessel coronary artery disease who are asymptomatic without evidence of ongoing ischemia if the procedure is performed between 24 hours and 28 days after a heart attack. In this time interval, guidelines indicate that PCI is not recommended in patients with one- or two- vessel disease and a totally occluded coronary artery if they are hemodynamically and electrically stable and have no ongoing or easily provoked chest pain. However for these patients or, a patient who responds favorably to initial fibrinolysis (treatment with a clot-busting drug), some physicians might use PCI selectively for those who don’t continue to do well on drug therapy alone.
Members of the writing group said the balance of evidence supports an early invasive strategy for PCI for patients with unstable angina or non-ST elevation heart attack (UA/NSTEMI), who are at moderate and higher risk, but noted one recent study suggests that in those patients who are initially stabilized on comprehensive medical therapy, PCI may be used selectively.
Thus, the guideline update says, a selective invasive strategy may be considered as an alternative treatment option in initially stabilized patients. It’s important to note that this treatment strategy received a lower level recommendation than that given to early PCI is the first line of treatment for “patients who have no additional serious conditions, who have blockages amenable to PCI, and who have characteristics for invasive therapy.”
In addition to treatment guidelines, the writing group also emphasized the importance of updated recommendations for secondary prevention of heart attacks. These recommendations carry stronger language about tobacco cessation and exposure to secondhand smoke and more comprehensive medical treatment strategies which are effective for controlling cholesterol and high blood pressure. Patients with diabetes are urged to ensure that their care is carefully coordinated between their primary care physicians and specialists and an annual flu shot is recommended for all patients with cardiovascular disease.
The writing group indicates that this focused update is based on clear analysis of the science and research available at a given point in time. They note the guidelines are continually reviewed for relevancy and as new data become available and validated, additional updates will be considered and issued as appropriate,
Individual recommendations updated in this focused update will be incorporated into future revisions and/or updates of the full-text guidelines.
About the American College of Cardiology:
The American College of Cardiology is leading the way to optimal cardiovascular care and disease prevention. The College is a 34,000-member nonprofit medical society and bestows the credential Fellow of the American College of Cardiology upon physicians who meet its stringent qualifications. The College is a leader in the formulation of health policy, standards and guidelines, and is a staunch supporter of cardiovascular research. The ACC provides professional education and operates national registries for the measurement and improvement of quality care. For more information visit www.acc.org.
About the American Heart Association
Founded in 1924, the American Heart Association today is the nation’s oldest and largest voluntary health organization dedicated to building healthier lives, free of heart disease and stroke. These diseases, America’s No. 1 and No. 3 killers, and all other cardiovascular diseases claim nearly 870,000 lives a year. In fiscal year 2006–07 the association invested more than $554 million in research, professional and public education, advocacy and community service programs to help all Americans live longer, healthier lives. To learn more, call 1-800-AHA-USA1 or visit americanheart.org.
About the Society for Cardiovascular Angiography and Interventions
Headquartered in Washington, DC, the Society for Cardiovascular Angiography and Interventions is a 4,000-member professional organization representing invasive and interventional cardiologists in 70 nations. SCAI’s mission is to promote excellence in invasive and interventional cardiovascular medicine through physician education and representation, and advancement of quality standards to enhance patient care. SCAI’s annual meeting has become the leading venue for education, discussion, and debate about the latest developments in this dynamic medical specialty.